Long Memory in the Australian Stock Market

In this paper, we re-examine the evidence of long memory in the Australian stock market. Using the rescaled range analysis, we find evidence of long memory and non-periodic cycles in the All Ordinaries Index. The result suggests that long memory is present in the Australian stock market. Furthermore, we add to the literature by investigating the presence of long memory in the daily ASX 50 index and its 50 constituent stocks using a GPH test proposed by Geweke and Porter-Hudak (1983). The results of individual stocks differ from those of the ASX 50 index and suggest that a common stock index is not representative of all market features.long memory, persistence, rescaled range analysis, GPH test

Sequence Based Optimization of Manufacturing Complexity in a Mixed Model Assembly Line

Increasing production variability while maintaining operation efficiency remains a critical issue in many manufacturing industries. While the adoption of mixed-model assembly lines enables the production of high product variety, it also makes the system more complex as variety increases. This paper proposes an information entropy-based methodology that quantifies and then minimizes the complexity through product sequencing. The theory feasibility is demonstrated in a series of simulations to showcase the impact of sequencing in controlling the system predictability and complexity. Hence, the framework not only serves as a tool to quantitatively assess the impact of complexity on total system performance but also provides means and insights into how complexity can be mitigated without affecting the overall manufacturing workload

Circuit Structure and Control Method to Reduce Size and Harmonic Distortion of Interleaved Dual Buck Inverter

A new circuit structure and control method for a high power interleaved dual-buck inverter are proposed. The proposed inverter consists of six switches, four diodes and two inductors, uses a dual-buck structure to eliminate zero-cross distortion, and operates in an interleaved mode to reduce the current stress of switch. To reduce the total harmonic distortion at low output power, the inverter is controlled using discontinuous-current-mode control combined with continuous-current-mode control. The experimental inverter had a power-conversion efficiency of 98.5% at output power = 1300 W and 98.3% at output power = 2 kW, when the inverter was operated at an input voltage of 400 V-DC, output voltage of 220 V-AC/60 Hz, and switching frequency of 20 kHz. The total harmonic distortion was < 0.66%, which demonstrates that the inverter is suitable for high-power dc-ac power conversion.11Ysciescopu

Efficient Acceleration-Level Formula of Bias Acceleration Satisfying Time Precedence for Operational Space Formulation

Operational space formulation has been used for robots to perform multi-tasks by taking advantage of dynamic consistency. Bias acceleration, which is an acceleration realized right after applying the control torque to a robot, compensates for the acceleration due to the higher priority tasks, thereby achieving the goal of the tasks with lower priority. Since the operational space formulation requires many computations during real-time control, there is a strong need to reduce the number of computations. We proposed an efficient acceleration-level bias acceleration formula while showing that the original bias acceleration formula could take 30-50% of the total computation for the operational space formulation. Moreover, we clarified the underlying time precedence of bias acceleration, which was implicitly provided in the original formula but was never clearly explained. Further, we have proved that the inefficiency of the original formula is due to the use of unnecessary full robot dynamics, the use of which is almost entirely eliminated in the proposed formula. Through extensive simulations and experiments, we have verified that the proposed formula needs 2-4% computations of the original, is independent of the Coriolis/centrifugal torque and the gravity torque, and is equivalent to the original formula. We expect that, with a deeper understanding of the bias acceleration, the proposed bias acceleration formula could promote the use of high degrees-of-freedom robots

Vertically aligned InGaN nanowires with engineered axial In composition for highly efficient visible light emission.

We report on the fabrication of novel InGaN nanowires (NWs) with improved crystalline quality and high radiative efficiency for applications as nanoscale visible light emitters. Pristine InGaN NWs grown under a uniform In/Ga molar flow ratio (UIF) exhibited multi-peak white-like emission and a high density of dislocation-like defects. A phase separation and broad emission with non-uniform luminescent clusters were also observed for a single UIF NW investigated by spatially resolved cathodoluminescence. Hence, we proposed a simple approach based on engineering the axial In content by increasing the In/Ga molar flow ratio at the end of NW growth. This new approach yielded samples with a high luminescence intensity, a narrow emission spectrum, and enhanced crystalline quality. Using time-resolved photoluminescence spectroscopy, the UIF NWs exhibited a long radiative recombination time (τr) and low internal quantum efficiency (IQE) due to strong exciton localization and carrier trapping in defect states. In contrast, NWs with engineered In content demonstrated three times higher IQE and a much shorter τr due to mitigated In fluctuation and improved crystal quality

MOF-Derived Cu@Cu2O Nanocatalyst for Oxygen Reduction Reaction and Cycloaddition Reaction

Research on the synthesis of nanomaterials using metal-organic frameworks (MOFs), which are characterized by multi-functionality and porosity, as precursors have been accomplished through various synthetic approaches. In this study, copper and copper oxide nanoparticles were fabricated within 30 min by a simple and rapid method involving the reduction of a copper(II)-containing MOF with sodium borohydride solution at room temperature. The obtained nanoparticles consist of a copper core and a copper oxide shell exhibited catalytic activity in the oxygen reduction reaction. The as-synthesized Cu@Cu2O core-shell nanocatalyst exhibited an enhanced limit current density as well as onset potential in the electrocatalytic oxygen reduction reaction (ORR). Moreover, the nanoparticles exhibited good catalytic activity in the Huisgen cycloaddition of various substituted azides and alkynes under mild reaction conditions

Simple and Reliable Position Sense Assessment Under Different External Torques: Toward Developing a Post-Stroke Proprioception Evaluation Device

Evaluation of position sense post-stroke is essential for rehabilitation. Position sense may be an output of a process needing position information, external torque, and the sense of effort. Even for healthy individuals, it is unclear whether external torque affects position sense. Thus, evaluation of position sense under different external torques in clinical settings is strongly needed. However, simple devices for measuring position sense under different external torques in clinical settings are lacking. Technologically advanced devices that may evaluate the elbow position sense under different torques were reported to be infeasible clinically because of device complexity and the need for technical experts when analyzing data. To address the unmet need, in this study, a simple and light elbow position sense measurement device was developed that allows clinicians to measure elbow position sense under different external torques in the form of position matching error objectively without any technical difficulties. The feasibility of the device, including intra-session intra-rater reliability and test-retest reliability over two consecutive days, was verified to be clinically applicable using tests with 25 healthy subjects. Thanks to its ease of use, high reliability, and ease of data analysis, it is expected that the device can help to evaluate the position sense post-stroke comprehensively