Design automation with the characteristics properties model and the property driven design for redesign

This paper presents a framework consisting of a mathematical model and an algorithm for representation, analysis and exploration of the design space in redesign problems. The framework develops and extends the existing formalism of the Characteristics Properties Model (CPM) and Property Driven Design (PDD). A platform independent quantitative model based on formal log-ic is presented to map the characteristics and properties, as well as the relations and dependencies between them, along with solution conditions. The model is based on generalization of existing mathematical design models and is support-ed by the development of an algorithm enabling property driven design. The re-sulting framework offers a rich and flexible syntax and vocabulary along with a mathematical and computational tool applicable to mechanical product design

Set-based design of mechanical systems with design robustness integrated

This paper presents a method for parameter design of mechanical products based on a set-based approach. Set-based concurrent engineering emphasises on designing in a multi-stakeholder environment with concurrent involvement of the stakeholders in the design process. It also encourages flexibility in design through communication in terms of ranges instead of fixed point values and subsequent alternative solutions resulting from intersection of these ranges. These alternative solutions can then be refined and selected according to the designers’ preferences and clients’ needs. This paper presents a model and tools for integrated flexible design that take into account the manufacturing variations as well as the design objectives for finding inherently robust solutions using QCSP transformation through interval analysis. In order to demonstrate the approach, an example of design of rigid flange coupling with a variable number of bolts and a choice of bolts from ISO M standard has been resolved and demonstrated

Tolerance analysis approach based on the classification of uncertainty (aleatory / epistemic)

Uncertainty is ubiquitous in tolerance analysis problem. This paper deals with tolerance analysis formulation, more particularly, with the uncertainty which is necessary to take into account into the foundation of this formulation. It presents: a brief view of the uncertainty classification: Aleatory uncertainty comes from the inherent uncertain nature and phenomena, and epistemic uncertainty comes from the lack of knowledge, a formulation of the tolerance analysis problem based on this classification, its development: Aleatory uncertainty is modeled by probability distributions while epistemic uncertainty is modeled by intervals; Monte Carlo simulation is employed for probabilistic analysis while nonlinear optimization is used for interval analysis.“AHTOLA” project (ANR-11- MONU-013

Digital Predistortion for Dual-Input Doherty Amplifiers

This paper presents a digital predistortion technique for dual-input Doherty power amplifiers. The proposed technique utilizes both RF inputs of the main and peak amplifiers in the digital predistorter. The effectiveness of the resulting dual-input predistorter is evaluated on a twoway Doherty amplifier operating at 2.14 GHz with 53.5 dBm peak output power. The experimental results demonstrate that the dual-input approach outperforms the conventional single-input predistortion technique by ∼3 dB in terms of adjacent channel leakage ratio

A statistical tolerance analysis approach for over-constrained mechanism based on optimization and Monte Carlo simulation

Tolerancing decisions can profoundly impact the quality and cost of the mechanism. To evaluate the impact of tolerance on mechanism quality, designers need to simulate the influences of tolerances with respect to the functional requirements. This paper proposes a mathematical formulation of tolerance analysis which integrates the notion of quantifier: ‘‘For all acceptable deviations (deviations which are inside tolerances), there exists a gap configuration such as the assembly requirements and the behavior constraints are verified’’ & ‘‘For all acceptable deviations (deviations which are inside tolerances), and for all admissible gap configurations, the assembly and functional requirements and the behavior constraints are verified’’. The quantifiers provide a univocal expression of the condition corresponding to a geometrical product requirement. This opens a wide area for research in tolerance analysis. To solve the mechanical problem, an approach based on optimization is proposed. Monte Carlo simulation is implemented for the statistical analysis. The proposed approach is tested on an over-constrained mechanism

Outcome Comparison of Endoscopic (Endonasal Trans-Sphenoidal) Repairs of CSS Leak vs. Transcranial Approach

Objective:   To compare the effectiveness of Endoscopic (Endonasal transsphenoidal) repair of CSF leak with transcranial approach in terms of post-operative complications like infection, recurrence and hospital stay. Material and Methods:  The comparative experimental randomized study was conducted in the Department of Neurosurgery Unit I, PGMI, Lahore General Hospital, Lahore. After approval from ethical committee this study was carried out in our unit. 40 subjects with the history of CSF leak were randomly divided into two groups; one was treated with endonasal trans-sphenoidal repair and another was treated with trans-cranial approach, the subjects were followed up for 1 year. Detailed history, neurological examination, preoperative CT and MRI scans were performed in all patients. Results:  The mean age of patients with CSF leak was 25.58 ± 14.38 years. Among the patients, 17 were females and 23 were male. The mean age of the female was 31.70 ± 14.29 years. The mean age of the male was 21.04 ± 12.95. The recurrence was observed in 2 (10%) of the patients treated with endoscopic technique and 1 (5%) of the patients treated with trans-cranial approach. Those patients were successfully repaired in a second operation. Overall success rate was 92.5%. One patient (2.50%) among the trans-cranial approach develops infection which was treated successfully. Conclusion:  The endoscopic repair of CSF leak is both safe and effective and should be considered as the standard procedure of choice in most of the cases

Implementation of lightweight machine learning-based intrusion detection system on IoT devices of smart homes

Smart home devices, also known as IoT devices, provide significant convenience; however, they also present opportunities for attackers to jeopardize homeowners’ security and privacy. Securing these IoT devices is a formidable challenge because of their limited computational resources. Machine learning-based intrusion detection systems (IDSs) have been implemented on the edge and the cloud; however, IDSs have not been embedded in IoT devices. To address this, we propose a novel machine learning-based two-layered IDS for smart home IoT devices, enhancing accuracy and computational efficiency. The first layer of the proposed IDS is deployed on a microcontroller-based smart thermostat, which uploads the data to a website hosted on a cloud server. The second layer of the IDS is deployed on the cloud side for classification of attacks. The proposed IDS can detect the threats with an accuracy of 99.50% at cloud level (multiclassification). For real-time testing, we implemented the Raspberry Pi 4-based adversary to generate a dataset for man-in-the-middle (MITM) and denial of service (DoS) attacks on smart thermostats. The results show that the XGBoost-based IDS detects MITM and DoS attacks in 3.51 ms on a smart thermostat with an accuracy of 97.59%.</p