CROPS - a decision-making aid tool for product redesign

Change Ranking of Product Subsystems (CROPS) is a computer program that is designed to act as a decision-making aid for designers during early stages of their product redesign process. It generates a ranking of all subsystems within the existing product design architecture based on their estimated redesign risk. This information assists designers in selecting the right existing subsystems to be initially changed to satisfy the driving requirements, which have to be quickly decided. In this program, evaluation of redesign risk captures both direct and indirect change effects that potentially result from the modification of each subsystem. Designers are provided with a relative reference as to how risky and extensive it is to change one subsystem over the others, which can be useful when they have options to pick between several subsystems to modify for the same redesign requirement

Subsystems change ranking methodology (SCRaM) for complex product redesign process

Product redesign is hardly a straightforward process, especially for complex products. The existence of intricate interrelationships between different components of product design architecture makes it more susceptible to change propagation phenomenon. In this case, redesign risk is not easy to predict since the change effects are being propagated to other components from the initiating change component. Because of this condition, choosing the right initiating change component is essential to control redesign process risks, apart from being able to successfully satisfy the product requirements. With this notion, this paper proposes a method that systematically ranks all components of an existing product design based on their estimated redesign risk. By having this information, designers can make a better redesign planning. The demonstration of this method is presented through an example aircraft redesign case study

APPLICATION OF SUBSYSTEMS CHANGE RANKING METHODOLOGY IN AIRCRAFT REDESIGN PROCESS

Redesigning an aircraft is hardly a straightforward task. Due to its high susceptibility to change effects propagation, it becomes very important to select the right initiating change components to minimize redesign development risks. With realization that there are often several different ways to redesign an existing aircraft for satisfying similar requirements, designers might require assistance in selecting suitable initiating change components in their redesign plan. A methodology that systematically ranks the subsystems of the chosen baseline design according to their estimated redesign risk is proposed here. It is strongly believed that making this information available to designers during the early redesign stages will help them to make a better redesign plan. KEY WORDS: subsystems ranking, aircraft redesign, redesign plan ABSTRAK: Reka semula sesebuah pesawat udara bukanlah satu tugas yang jelas dan mudah. Memandangkan ia mudah rentan terhadap perubahan rambatan, amatlah penting untuk memilih penukaran komponen yang sesuai pada peringkat awal untuk mengurangkan masalah pembangunan reka semula. Menyedari bahawa terdapat beberapa cara untuk mereka semula pesawat udara yang sedia ada, demi memperolehi keputusan keperluan yang serupa dan memberansangkan, pereka wajar mendapatkan bantuan dari segi penukaran komponen yang sesuai pada peringkat awal pembangunan reka semula yang menepati rangka pelan reka bentuk mereka. Metodologi yang sistematik meletakkan subsistem dasar reka bentuk yang dipilih, berdasarkan anggaran risiko reka bentuk semula dicadangkan di dalam kertas kerja ini. Adalah diyakini bahawa dengan memperolehi informasi ini di peringkat permulaan reka bentuk, ia dapat menolong pereka merangka pelan reka cipta yang lebih baik

Modified Quasi-Steady State Model of DC System for Transient Stability Simulation under Asymmetric Faults

As using the classical quasi-steady state (QSS) model could not be able to accurately simulate the dynamic characteristics of DC transmission and its controlling systems in electromechanical transient stability simulation, when asymmetric fault occurs in AC system, a modified quasi-steady state model (MQSS) is proposed. The model firstly analyzes the calculation error induced by classical QSS model under asymmetric commutation voltage, which is mainly caused by the commutation voltage zero offset thus making inaccurate calculation of the average DC voltage and the inverter extinction advance angle. The new MQSS model calculates the average DC voltage according to the actual half-cycle voltage waveform on the DC terminal after fault occurrence, and the extinction advance angle is also derived accordingly, so as to avoid the negative effect of the asymmetric commutation voltage. Simulation experiments show that the new MQSS model proposed in this paper has higher simulation precision than the classical QSS model when asymmetric fault occurs in the AC system, by comparing both of them with the results of detailed electromagnetic transient (EMT) model of the DC transmission and its controlling system

Novel TLR7/8 agonists promote activation of HIV-1 latent reservoirs and human T and NK cells

Antiretroviral therapy can successfully suppress HIV-1 replication to undetectable levels but fails to eliminate latent and persistent HIV-1 reservoirs. Recent studies have focused on the immunomodulatory agents such as Toll-like receptor 7 and 8 (TLR7 and TLR8) capable of activating, thereby rendering the reservoir susceptible to antiretroviral inhibition and immune recognition and elimination. In this context, this study focused on generating a diverse repertoire of TLR7/8 agonists to identify more potent candidates for activating latent HIV-1 and immune cells’ response. Through combinational strategies of computer-aided design and biological characterization, 159 pyrido [3,2-d] pyrimidine and pyridine-2-amine-based derivatives were synthesized. Of which, two TLR7/8 dual and one TLR8-specific agonists with exceptionally high potency in activating HIV-1 latent reservoirs in cell lines and PBMCs of patients with persistent and durable virologic controls were identified. Particularly, these agonists appeared to enhance NK and T cells activity, which were correlated with the degree of surface activation markers. The outcome of this study highlights the remarkable potential of TLR7/8 agonists in simultaneously activating HIV-1 from the latently infected cells and augmenting immune effector cells

Hippo signalling governs cytosolic nucleic acid sensing through YAP/TAZ-mediated TBK1 blockade

The Hippo pathway senses cellular conditions and regulates YAP/TAZ to control cellular and tissue homeostasis, while TBK1 is central for cytosolic nucleic acid sensing and antiviral defence. The correlation between cellular nutrient/physical status and host antiviral defence is interesting but not well understood. Here we find that YAP/TAZ act as natural inhibitors of TBK1 and are vital for antiviral physiology. Independent of transcriptional regulation and through the transactivation domain, YAP/TAZ associate directly with TBK1 and abolish virus-induced TBK1 activation, by preventing TBK1 Lys63-linked ubiquitylation and the binding of adaptors/substrates. Accordingly, YAP/TAZ deletion/depletion or cellular conditions inactivating YAP/TAZ through Lats1/2 kinases relieve TBK1 suppression and boost antiviral responses, whereas expression of the transcriptionally inactive YAP dampens cytosolic RNA/DNA sensing and weakens the antiviral defence in cells and zebrafish. Thus, we describe a function of YAP/TAZ and the Hippo pathway in innate immunity, by linking cellular nutrient/physical status to antiviral host defence

Electromagnetic transient modelling and simulation of power converters based on a piecewise generalised state–space averaging method

Common averaging methods are studied for modelling a grid-connected converter in renewable energy domain to balance accuracy and efficiency of electromagnetic transient simulation. A piecewise generalised state–space averaging (P-GSSA) method is proposed for converters with large-scale renewable energy connected to the grid. The piecewise technique is applied to the GSSA model of converters, which combine time segment with similar operating characteristics. In addition, multi-time scale modelling is successfully achieved for the grid-connected converters in the renewable energy domain. An example is simulated according to the P-GSSA model proposed in this paper, and simulation results show that the proposed model can provide an efficient simulation of power converters connected to the grid in the domain of large-scale renewable energy

APPLICATION OF SUBSYSTEMS CHANGE RANKING METHODOLOGY IN AIRCRAFT REDESIGN PROCESS

Redesigning an aircraft is hardly a straightforward task. Due to its high susceptibility to change effects propagation, it becomes very important to select the right initiating change components to minimize redesign development risks. With realization that there are often several different ways to redesign an existing aircraft for satisfying similar requirements, designers might require assistance in selecting suitable initiating change components in their redesign plan. A methodology that systematically ranks the subsystems of the chosen baseline design according to their estimated redesign risk is proposed here. It is strongly believed that making this information available to designers during the early redesign stages will help them to make a better redesign plan. <br /> KEY WORDS: subsystems ranking, aircraft redesign, redesign plan <p>ABSTRAK: Reka semula sesebuah pesawat udara bukanlah satu tugas yang jelas dan mudah. Memandangkan ia mudah rentan terhadap perubahan rambatan, amatlah penting untuk memilih penukaran komponen yang sesuai pada peringkat awal untuk mengurangkan masalah pembangunan reka semula. Menyedari bahawa terdapat beberapa cara untuk mereka semula pesawat udara yang sedia ada, demi memperolehi keputusan keperluan yang serupa dan memberansangkan, pereka wajar mendapatkan bantuan dari segi penukaran komponen yang sesuai pada peringkat awal pembangunan reka semula yang menepati rangka pelan reka bentuk mereka. Metodologi yang sistematik meletakkan subsistem dasar reka bentuk yang dipilih, berdasarkan anggaran risiko reka bentuk semula dicadangkan di dalam kertas kerja ini. Adalah diyakini bahawa dengan memperolehi informasi ini di peringkat permulaan reka bentuk, ia dapat menolong pereka merangka pelan reka cipta yang lebih baik.</p

Control of photovoltaic power integration based on multi-terminal VSC–HVDC system

In order to solve the problem of long-distance transmission of large-scale photovoltaic power stations, a multi-terminal voltage source converter-based high-voltage direct current (VSC–HVDC) system based on a DC voltage-active power-AC voltage control strategy, which is connected with photovoltaic power stations, is designed in this study. In order to verify the feasibility of the method, a model of a five-terminal parallel system is established by MATLAB/Simulink, which includes two photovoltaic power stations and a passive network. A series of simulations are carried out based on the model. The results show that the active power of the system can be automatically balanced when the output power of photovoltaic power stations changes. When the three-phase short-circuit fault occurs in power grid, the photovoltaic power stations can still run in a stable state and have better fault ride-through ability

Modeling and Equivalence of Integrated Power Generation System of Wind, Photovoltaic and Energy Storage

7 Halama