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Astrodynamics ◽  
2022 ◽  
Vol 6 (1) ◽  
pp. 17-26
Author(s):  
Minwen Guo ◽  
Xiangyu Huang ◽  
Maodeng Li ◽  
Jinchang Hu ◽  
Chao Xu

AbstractTo meet the requirements of the Tianwen-1 mission, adaptive entry guidance for entry vehicles, with low lift-to-drag ratios, limited control authority, and large initial state bias, was presented. Typically, the entry guidance law is divided into four distinct phases: trim angle-of-attack phase, range control phase, heading alignment phase, and trim-wing deployment phase. In the range control phase, the predictor—corrector guidance algorithm is improved by planning an on-board trajectory based on the Mars Science Laboratory (MSL) entry guidance algorithm. The nominal trajectory was designed and described using a combination of the downrange value and other states, such as drag acceleration and altitude rate. For a large initial state bias, the nominal downrange value was modified onboard by weighing the landing accuracy, control authority, and parachute deployment altitude. The biggest advantage of this approach is that it allows the successful correction of altitude errors and the avoidance of control saturation. An overview of the optimal trajectory design process, including a discussion of the design of the initial flight path angle, relevant event trigger, and transition conditions between the four phases, was also presented. Finally, telemetry data analysis and post-flight assessment results were used to illustrate the adaptive guidance law, create good conditions for subsequent parachute reduction and power reduction processes, and gauge the success of the mission.


2021 ◽  
Vol 1 (4) ◽  
pp. 64-92
Author(s):  
Ahmad Abdollah Salim Al Mashaikhie ◽  
Mohd Nazri Mohd Noor

This study aims to identify the reality of governance for the Financial and Administrative Control Authority in the Sultanate of Oman. The problem of the study is that the Financial and Administrative Control Authority in the Sultanate of Oman is making many efforts to popularize procedures and methods through the tasks carried out by the Financial and Administrative Control Authority to improve the economic performance of institutions and to discover financial and administrative violations that workers may commit during a certain period of time. The importance of governance is highlighted in many matters, most notably the need to respect the laws and regulations that institutions follow, and that governance contributes to exposing professional errors and increasing the experiences of workers, especially those working in the financial and administrative fields, in order to achieve the highest levels of job discipline. Governance contributes significantly to achieving the long- and medium-term goals of institutions and companies. The study followed the descriptive analytical approach to describe and analyze the role of governance in the financial and administrative control body in the Sultanate of Oman. The current study concluded that governance in the Financial and Administrative Control Authority in the Sultanate of Oman is based on several pillars, including work ethics in financial institutions and the continuity of oversight, follow-up and oversight. The study recommended the necessity of applying governance mechanisms in Omani institutions.


Author(s):  
Ahmad Abdollah Salim Al Mashaikhie ◽  
Mohammad Nazri Mohammad Nor

The study aims to identify transparency in the Financial and Administrative Control Authority in the Sultanate of Oman. The problem of the study lies in the low status of Omani institutions in the Global Corruption Perceptions Index, which reflects the spread of financial and administrative corruption in the Financial and Administrative Control Authority in the Sultanate of Oman. The study highlights the importance of shedding light on transparency in the Financial and Administrative Control Authority in the Sultanate of Oman. The study followed the descriptive analytical approach to describe and analyze transparency in the Financial and Administrative Control Authority in the Sultanate of Oman. The study reached many results, including that the Financial and Administrative Control Authority is trying to apply governance standards in accordance with the instructions issued in this regard. The results showed that one of the most important dimensions of transparency is the possibility of separating powers, practicing transparency in the areas of public life, and activating the law. The results also showed that the pillars of transparency are clarity of work rules in institutions, the dimensions of suspicious personalities from financial and administrative work, rationalization of consumption, and ensuring access to information by the Financial and Administrative Control Authority in the Sultanate of Oman. The results concluded that the application of transparency greatly contributed to enhancing the freedom of access to information, and the reports of the supervisory bodies on the situation inside the institutions received a lot of attention from the public, which indicates the importance of the prominent media role played by the supervisory institutions in order to enhance the role of transparency. The study recommended the need to expand the application of transparency elements in the financial and administrative control body in the Sultanate of Oman. The study also recommended that the practice of transparency contributes to the spread of more freedoms in society, but it is of the opinion that the application of transparency should not be limited to the public employee in institutions only without looking at the higher leaders, as these leaders may be one of the causes of financial and administrative corruption. The study also recommended that the supervisory authorities have many foundations and standards in the matter of punishment and accountability without prejudice to the rights of the employee, as well as researching the reasons for his fraud and obtaining illegal funds from the institution in which he works.


Author(s):  
Carmine Varriale ◽  
Mark Voskuijl

AbstractThis paper presents a generic trim problem formulation, in the form of a constrained optimization problem, which employs forces and moments due to the aircraft control surfaces as decision variables. The geometry of the Attainable Moment Set (AMS), i.e. the set of all control forces and moments attainable by the control surfaces, is used to define linear equality and inequality constraints for the control forces decision variables. Trim control forces and moments are mapped to control surface deflections at every solver iteration through a linear programming formulation of the direct Control Allocation algorithm. The methodology is applied to an innovative box-wing aircraft configuration with redundant control surfaces, which can partially decouple lift and pitch control, and allow direct lift control. Novel trim applications are presented to maximize control authority about the lift and pitch axes, and a “balanced” control authority. The latter can be intended as equivalent to the classic concept of minimum control effort. Control authority is defined on the basis of control forces and moments, and interpreted geometrically as a distance within the AMS. Results show that the method is able to capitalize on the angle of attack or the throttle setting to obtain the control surfaces deflections which maximize control authority in the assigned direction. More conventional trim applications for minimum total drag and for assigned angle of elevation are also explored.


2021 ◽  
Author(s):  
Jannet Usai ◽  
Zita Ekeocha ◽  
Stephen Robert Byrn ◽  
Kari L Clase

Unregistered traditional medicines pose a huge public health threat as the safety and efficacy of these products is unknown. The issue this study addresses is the inadequate regulatory measures for herbal medicines in Zimbabwe. This project was done to describe the current registration process of traditional medicines in Zimbabwe, and to identify the gaps and opportunities they present to improve the regulatory landscape. Regulations and laws governing the registration of herbal medicines in the country and published research on legislation of herbal medicines were reviewed. Two parallel regulatory bodies both registering and controlling the sale of herbal medicines were identified. The Medicines Control Authority of Zimbabwe (MCAZ) and the Traditional Medical Practitioners Association (TMPA) both derive their authority to regulate from the ministry of health and were established through the act of parliament which gives these authorities power to regulate the quality and sale of traditional medicines without giving a prescriptive way of doing it. The registration process, and product evaluations for the two authorities are different. While the MCAZ has a clearly defined registration process, the TMPA does not. However, MCAZ has not been very successful in registering local products with the majority of the registered herbal products being imports and only 2% of total registered products being local herbs. As a recommendation, there is need for collaboration between the regulatory bodies for consistence in quality of herbal products on the market and to improve registration of local herbal products. Developing monographs for local herbs commonly used in the country will also assist local manufacturer to fulfill the quality requirements and successful compilation of dossiers for product registration.


2021 ◽  
Vol 6 (10) ◽  
pp. 319-333
Author(s):  
Mastika Nasrun ◽  
Norazlina Abdul Aziz ◽  
Nurasma Yahaya ◽  
Sarah Munirah Abdullah

During the spread of the COVID-19 pandemic, many health-related industries were alarmed and pressured to innovate solutional vaccines to reduce the effect of the COVID-19 pandemic. Extra effort and lab activities had taken place in several jurisdictions to respond to the increased demand for the COVID-19 vaccine. With these attempts, various vaccines were created and entered the market. All countries designed their own COVID-19 programme in the route to combat the viruses. These countries showed their willingness to invest to secure access to vaccines. In parallel to this development, the vaccination program is bombarded with several issues such as safety assurance, equal access to the vaccine, and protests by the anti-vaccine group. The inability to address these issues will jeopardise the success of building herd immunity which is the core in eradicating COVID-19 cases. Thus, this study explored and analysed the issues and challenges to have an effective vaccination program in a battle against the spread of the COVID-19 virus. It is a comparative study between Malaysia and Australia that includes safety measures, anti-vaccine groups and access to vaccines. This study adopts a qualitative method utilising the doctrinal study on the legal framework that describes the scope and limitation of power accorded to the Drug Control Authority of the selected jurisdictions. The research activities also include semi-structured interviews with relevant authorities using online interviews. The data are analysed using content and thematic analysis. Findings to this study may assist in identifying the loopholes within the administrative control on the vaccination program adopted by Malaysia.


Author(s):  
Haithem E. Taha ◽  
Ahmed Hassan ◽  
Moatasem Fouda

AbstractIn this paper, we review the concept of Lie brackets and how it can be exploited in generating motion in unactuated directions through nonlinear interactions between two or more control inputs. Applying this technique to the airplane flight dynamics near stall, a new rolling mechanism is discovered through nonlinear interactions between the elevator and the aileron control inputs. This mechanism, referred to as the Lie Bracket Roll Augmentation (LIBRA) mechanism, possesses a significantly higher roll control authority near stall compared to the conventional roll mechanism using ailerons only; it produces more than an order-of-magnitude stronger roll motion over the first second. The main contribution of this paper is to study the nonlinear flight physics that lead to this superior performance of the LIBRA mechanism. In fact, the LIBRA performance in free flight (six DOF) is double that in a confined environment of two-DOF roll-pitch dynamics. The natural feedback from the airplane motion (roll, yaw, and sideslip) into the LIBRA mechanism boosts its performance through interesting nonlinear interplay between roll and yaw, while exploiting some of the changes in the airplane characteristics near stall.


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