Analyzing helicopter evasive maneuver effectiveness against rocket-propelled grenades

It has long been acknowledged that military helicopters are vulnerable to ground-launched threats, in particular, the RPG-7 rocket-propelled grenade. Current helicopter threat mitigation strategies rely on a combination of operational tactics and selectively placed armor plating, which can help to mitigate but not entirely remove the threat. However, in recent years, a number of active protection systems designed to protect land-based vehicles from rocket and missile fire have been developed. These systems all use a sensor suite to detect, track, and predict the threat trajectory, which is then employed in the computation of an intercept trajectory for a defensive kill mechanism. Although a complete active protection system in its current form is unsuitable for helicopters, in this paper, it is assumed that the active protection system’s track and threat trajectory prediction subsystem could be used offline as a tool to develop tactics and techniques to counter the threat from rocket-propelled grenade attacks. It is further proposed that such a maneuver can be found by solving a pursuit–evasion differential game. Because the first stage in solving this problem is developing the capability to evaluate the game, nonlinear dynamic and spatial models for a helicopter, RPG-7 round, and gunner, and evasion strategies were developed and integrated into a new simulation engine. Analysis of the results from representative vignettes demonstrates that the simulation yields the value of the engagement pursuit–evasion game. It is also shown that, in the majority of cases, survivability can be significantly improved by performing an appropriate evasive maneuver. Consequently, this simulation may be used as an important tool for both designing and evaluating evasive tactics and is the first step in designing a maneuver-based active protection system, leading to improved rotorcraft survivability

Emergent Behavior Development and Control in Multi-Agent Systems

Emergence in natural systems is the development of complex behaviors that result from the aggregation of simple agent-to-agent and agent-to-environment interactions. Emergence research intersects with many disciplines such as physics, biology, and ecology and provides a theoretical framework for investigating how order appears to spontaneously arise in complex adaptive systems. In biological systems, emergent behaviors allow simple agents to collectively accomplish multiple tasks in highly dynamic environments; ensuring system survival. These systems all display similar properties: self-organized hierarchies, robustness, adaptability, and decentralized task execution. However, current algorithmic approaches merely present theoretical models without showing how these models actually create hierarchical, emergent systems. To fill this research gap, this dissertation presents an algorithm based on entropy and speciation - defined as morphological or physiological differences in a population - that results in hierarchical emergent phenomena in multi-agent systems. Results show that speciation creates system hierarchies composed of goal-aligned entities, i.e. niches. As niche actions aggregate into more complex behaviors, more levels emerge within the system hierarchy, eventually resulting in a system that can meet multiple tasks and is robust to environmental changes. Speciation provides a powerful tool for creating goal-aligned, decentralized systems that are inherently robust and adaptable, meeting the scalability demands of current, multi-agent system design. Results in base defense, k-n assignment, division of labor and resource competition experiments, show that speciated populations create hierarchical self-organized systems, meet multiple tasks and are more robust to environmental change than non-speciated populations

Pursuing fit: a grounded theory of e-recruitment in Namibia – an integrated jobseeker and agency perspective

The purpose of this study was to identify the main concern of jobseekers and recruitment agencies in electronic recruitment (e-recruitment) and determine how it was resolved. The country of Namibia was chosen for the study because many of its jobseekers and recruitment agencies are adopting e-recruitment to overcome challenges in their recruitment context. In order to meet the purpose of the study, Classic Grounded Theory Methodology (classic-GTM) was used. Through the application of classic-GTM it emerged that jobseekers' and recruitment agencies' perspectives on e-recruitment are varied and shifting, which together with the dynamics in information technology bring many possibilities and fluidity of stakeholders' behaviour. Therefore, jobseekers and recruitment agencies are mainly concerned about Fit or lack thereof between their conceptualizations of Objects of Concern (namely information technology, jobseekers, job providers (recruitment agencies and employers) and jobs) in such a dynamic environment. Pursuing Fit emerged as the core variable (core category) representing how the participants continuously resolved their main concern. Two sub-categories constituting Pursuing Fit are Interpreting Fit and Positioning for Fit and they explain how stakeholders interpret e-recruitment concepts and position themselves and other Objects of Concern based on interpretation. Recruitment is likely to take place when Objects of Concern relate in a desirable (fitting) manner. The study's contribution to knowledge is through the theory of Pursuing Fit that suggests a systematic way of understanding e-recruitment and of conceptualizing information technology in e-recruitment to increase chances of recruitment. Implications common for both jobseekers and recruitment agencies are context awareness and flexibility. Context awareness allows stakeholders to interpret Objects of Concern based on the context and flexibility makes it possible to change from a previously held position. The study can be used as the foundation for research involving multiple stakeholders in e-recruitment. In conclusion, e-recruitment is a process of meaning creation in which stakeholders interpret concepts and based on the meanings relate the concepts with each other

A SCHOLARLY CONSIDERATION ON THE THEORIES AND LITERATURE OF TAX REFORMS IN SIERRA LEONE

This study examines how tax reforms have been implemented and how it has influenced Sierra Leone's ability to streamline fiscal structures. The topic of tax revenue mobilization is becoming more and more popular and crucial for emerging nations. The fiscal arrangement that exists between taxpayers and the current political administration is a fiduciary relationship that binds both parties to the right and obligation to effectively and efficiently mobilize revenues. The tax system in use has had a significant impact on government revenue since it allows for loopholes, dishonest tax authorities, inadequate data, and many other issues. This study also applauds the government for strengthening corporate tax authority plans and putting local restrictions on large corporations and foreign governments who conduct business in Sierra Leone. By doing this, taxpayers and tax authorities will be encouraged to be accountable, transparent, and compliant. Additionally, Sierra Leone's tax administration underwent a number of modifications between 2014 and 2019, although nothing is known about how well those reforms fared in terms of raising tax revenue. In fact, reform as a factor affecting tax collection has received little attention in the research on what motivates domestic resource mobilization. The paper evaluates whether reforms are crucial for raising tax revenue by taking into account various aspects of reforms in the tax administration, including tax-related reforms and reforms related to institutions, and using various econometric methods based on ordinary least squares, instrumental variable two-stage least squares, and iteratively reweighted least squares. According to the findings, tax reforms, institutional reforms, and all other reforms put together have greatly improved tax revenue performance. The main takeaway is that greater institutional and tax-related reforms are essential for sustainingly increasing tax revenue collection. JEL: E61, E62, P35  Article visualizations