Linear manipulator: Motion control of an n-link robotic arm mounted on a mobile slider.

Linear manipulators are versatile linear robotics systems that can be reprogrammed to accommodate product changes quickly and are flexible to meet unique requirements. Such robotic systems tend to have higher accuracy, making them the perfect automation solution for those mundane, repetitious tasks. With the demand for linear systems in real-life applications expanding consistently, this paper addresses motion planning and control (MPC) of a new modified unanchored linear manipulator consisting of an n-link robotic arm mounted on a mobile slider along a rail. Using the method of the Lyapunov-based Control Scheme (LbCS), new centralized acceleration-based controllers are designed for the navigation of the system to an unreachable target. Via the scheme, the unanchored manipulator can perform assigned tasks with enhanced reachability. The limitations and singularities of the linear manipulator are treated as artificial obstacles in this motion control scheme. The robotic arm manipulator utilized in this research can reposition its base link to a desired location in the workplace due to changes in work requirements. The effectiveness of the motion planner and the resulting acceleration-based control laws are validated numerically using the Runge-Kutta Method and illustrated via computer simulations. The controllers devised in this research can solve specific and targeted motion control problems of smart cities' modern mechanical systems. The unanchored linear manipulator could be used in various disciplines where pick-and-place, assembly, material handling, and surgical procedures are required.

Information and communications technology, health, and gender equality: Empirical evidence from a panel of Pacific developing economies.

Information and communications technology (ICT) has been widely embraced in many developing economies in recent times. Extant research reveals that ICT increases economic growth. Beyond economic growth, improved access to information, markets and economic opportunities via information and communications technology have the potential to influence other dimensions of public welfare. This study quantitatively examines the effects of ICT on selected health and gender dimensions of Pacific Island developing countries' populations. The results show a statistically significant and positive impact of ICT on health and gender outcomes. Our results are robust with an alternative modeling approach, different control variables, and different measures of health and gender outcomes. We further establish that the health outcome of technology has a valid pass-through of income. The study suggests policy implications for the Pacific and other developing countries striving to enhance the health and gender outcomes of SGDs.

Switch controllers of an n-link revolute manipulator with a prismatic end-effector for landmark navigation.

Robotic arms play an indispensable role in multiple sectors such as manufacturing, transportation and healthcare to improve human livelihoods and make possible their endeavors and innovations, which further enhance the quality of our lives. This paper considers such a robotic arm comprised of n revolute links and a prismatic end-effector, where the articulated arm is anchored in a restricted workspace. A new set of stabilizing switched velocity-based continuous controllers was derived using the Lyapunov-based Control Scheme (LbCS) from the category of classical approaches where switching of these nonlinear controllers is invoked by a new rule. The switched controllers enable the end-effector of the robotic arm to navigate autonomously via a series of landmarks, known as hierarchal landmarks, and finally converge to its equilibrium state. The interaction of the inherent attributes of LbCS that are the safeness, shortness and smoothness of paths for motion planning bring about cost and time efficiency of the controllers. The stability of the switched system was proven using Branicky's stability criteria for switched systems based on multiple Lyapunov functions and was numerically validated using the RK4 method (Runge-Kutta method). Finally, computer simulation results are presented to show the effectiveness of the continuous time-invariant velocity-based controllers.

Determinants of Exports in a Small and Vulnerable Economy: Fiji Islands-A Disaggregated Analysis.

The previous studies of exports performance in Fiji were carried out at the aggregate level. We conduct a disaggregated analysis of exports of three major products, namely, sugar, tourism, and gold. This analysis is useful for developing sector-based export promotion policies. The long run as well as dynamic export demand functions are estimated at the aggregate and disaggregate levels. The results identify a number of factors such as trading partner income, relative prices, productivity shocks, natural disasters, political disturbances, and the exchange rate that affect the export demand for sugar, tourism, and gold, though not in the same way. For instance, tourism and sugar enjoy the highest income elasticity. Sugar export is adversely affected by natural calamities and political upheavals. The political upheavals also affect tourism adversely in Fiji. The exchange rate affects the export of sugar more than others. The idea that devaluation will promote exports in Fiji needs careful investigation because results show that this will happen with a high cost, i.e. 5% nominal devaluation will be required to increase real exports by 1%.

Les études précédentes sur la performance des exportations aux Fidji ont été réalisées au niveau global. Nous effectuons une analyse désagrégée des exportations de trois produits principaux, à savoir le sucre, le tourisme et l'or. Cette analyse est utile pour développer des politiques sectorielles de promotion des exportations. Nous estimons au niveau global et au niveau désagrégé des projections sur le long terme, ainsi que des fonctions dynamiques de demande d'exportation. Les résultats identifient un certain nombre de facteurs, tels que le revenu des partenaires commerciaux, les prix relatifs, les chocs de productivité, les catastrophes naturelles, les troubles politiques et les variations du taux de change, qui affectent la demande d'exportation pour le sucre, le tourisme et l'or, bien que l'impact soit différent. Par exemple, le tourisme et le sucre bénéficient de l'élasticité du revenu la plus élevée. L'exportation de sucre est affectée par les catastrophes naturelles et les bouleversements politiques. Les bouleversements politiques affectent également le tourisme dans les îles Fidji. Les variations du taux de change affectent l'exportation de sucre plus que les autres produits. Il faut soigneusement étudier l'idée selon laquelle, aux Fidji, la dévaluation monétaire va favoriser les exportations, car les résultats montrent que cela ne se produira qu'avec un coût élevé, c'est-à-dire qu'une dévaluation nominale de 5% sera nécessaire pour augmenter les exportations réelles de 1%.

Projecting populations for major Pacific Island countries with and without COVID-19: pro-active insights for population policy.

The paper projects aggregate populations of six Pacific Island countries in both pre- and post-COVID19 scenarios using a Cohort Component Method for the period 2020-2060. It uses baseline indicators resembling China and Italy's experiences and finds that Pacific countries could experience a fatality rate between 5 and 20% due to the pandemic. It also finds that most Pacific Island countries would experience higher fatalities in the older age groups, consistent with what is being witnessed in other countries around the world. The analysis also shows that while the risk escalates for people over 50 years onward in all other sample countries, in Fiji, those in the age range of 60 years or more are at higher risk. The findings also indicate that for all countries, the fatality rate for 80 years and older is about 50%. The population projections show that Fiji will be most impacted, while others will experience around 2% initial population decline. The convergence to baseline is found to be slow (except for Tonga) in most Pacific countries. Consequently, the paper suggests a cautious approach in dealing with the current crisis.