Search results for: adaptive stiffness
1347 Adaptive Multipath Mitigation Acquisition Approach for Global Positioning System Software Receivers
Authors: Animut Meseret Simachew
Abstract:
Parallel Code Phase Search Acquisition (PCSA) Algorithm has been considered as a promising method in GPS software receivers for detection and estimation of the accurate correlation peak between the received Global Positioning System (GPS) signal and locally generated replicas. GPS signal acquisition in highly dense multipath environments is the main research challenge. In this work, we proposed a robust variable step-size (RVSS) PCSA algorithm based on fast frequency transform (FFT) filtering technique to mitigate short time delay multipath signals. Simulation results reveal the effectiveness of the proposed algorithm over the conventional PCSA algorithm. The proposed RVSS-PCSA algorithm equalizes the received carrier wiped-off signal with locally generated C/A code.Keywords: adaptive PCSA, detection and estimation, GPS signal acquisition, GPS software receiver
Procedia PDF Downloads 1111346 Channel Estimation/Equalization with Adaptive Modulation and Coding over Multipath Faded Channels for WiMAX
Authors: B. Siva Kumar Reddy, B. Lakshmi
Abstract:
WiMAX has adopted an Adaptive Modulation and Coding (AMC) in OFDM to endure higher data rates and error free transmission. AMC schemes employ the Channel State Information (CSI) to efficiently utilize the channel and maximize the throughput and for better spectral efficiency. This CSI has given to the transmitter by the channel estimators. In this paper, LSE (Least Square Error) and MMSE (Minimum Mean square Error) estimators are suggested and BER (Bit Error Rate) performance has been analyzed. Channel equalization is also integrated with with AMC-OFDM system and presented with Constant Modulus Algorithm (CMA) and Least Mean Square (LMS) algorithms with convergence rates analysis. Simulation results proved that increment in modulation scheme size causes to improvement in throughput along with BER value. There is a trade-off among modulation size, throughput, BER value and spectral efficiency. Results also reported the requirement of channel estimation and equalization in high data rate systems.Keywords: AMC, CSI, CMA, OFDM, OFDMA, WiMAX
Procedia PDF Downloads 3891345 Experimental Studies of Spiral-Confined HSCFST Columns under Uni-Axial Compression
Authors: Mianheng Lai, Johnny Ching Ming Ho, Hoat Joen Pam
Abstract:
Concrete-filled-steel-tube (CFST) columns are becoming increasingly popular owing to the superior behavior contributed by the composite action. However, this composite action cannot be fully developed because of different dilation properties between steel tube and concrete. During initial compression, there will be de-bonding between the constitutive materials. As a result, the strength, initial stiffness and ductility of CFST columns reduce significantly. To resolve this problem, external confinement in the form of spirals is proposed to improve the interface bonding. In this paper, a total of 14CFST columns with high-strength as well as ultra-high-strength concrete in-filled were fabricated and tested under uni-axial compression. From the experimental results, it can be concluded that the proposed spirals can improve the strength, initial stiffness, ductility and the interface bonding condition of CFST columns by restraining the lateral expansion of steel tube and core concrete. Moreover, the failure modes of confined core concrete change due to the strong confinement provided by spirals.Keywords: concrete-filled-steel-tube, confinement, failure mode, high-strength concrete, spirals
Procedia PDF Downloads 3471344 Pragmatism in Adaptive Reuse of Obsolete Industrial Land in China
Authors: Yong Li
Abstract:
Major cities in China has experienced a shift from production based on manufacturing industry to tertiary industry. How to make a better use of existing obsolete industrial land within urban cores has become a difficult problem for many policymakers. City governments regard old manufacturing industrial land as an important source of land to facilitate the development of the cities. Despite the announcement of policies in promoting that, a large portion of industrial land is still not properly redeveloped and most of them became obsolete. The study uses the project of Xinyi International Club as a case to examine the process of adaptive reuse of obsolete industrial space in Guangzhou, China. It attempts to elucidate the underlying mechanisms by identifying the key forces from both the government and the private sectors in influencing the process. The study found that market forces in transforming industrial space are exerting a strong impact on the existing land use planning system in Chinese cities. Pragmatic relaxation of the formal land use the regulatory framework and government supportive land-use intervention have also been crucial towards achieving successful implementation of the restructuring project and making it a showcase. This study questions whether these extraordinary measures, in particular, the use of temporary land use permit, are sustainable in facilitating the transformation of derelict industrial land, and in informing future industrial land-use restructuring policies. It concludes that, while the land use regulatory system in China is becoming increasingly dynamic and flexible, it remains ill-equipped in responding positively to the market, which is characterized by an increasing bargaining power of the private sector. A comprehensive appraisal of the overall impacts of these adaptive re-uses on society is wanting.Keywords: China, land alteration, obsolete industrial properties, urban planning
Procedia PDF Downloads 1421343 Evaluation of Hybrid Viscoelastic Damper for Passive Energy Dissipation
Authors: S. S. Ghodsi, M. H. Mehrabi, Zainah Ibrahim, Meldi Suhatril
Abstract:
This research examines the performance of a hybrid passive control device for enhancing the seismic response of steel frame structures. The device design comprises a damper which employs a viscoelastic material to control both shear and axial strain. In the design, energy is dissipated through the shear strain of a two-layer system of viscoelastic pads which are located between steel plates. In addition, viscoelastic blocks have been included on either side of the main shear damper which obtains compressive strains in the viscoelastic blocks. These dampers not only dissipate energy but also increase the stiffness of the steel frame structure, and the degree to which they increase the stiffness may be controlled by the size and shape. In this research, the cyclical behavior of the damper was examined both experimentally and numerically with finite element modeling. Cyclic loading results of the finite element modeling reveal fundamental characteristics of this hybrid viscoelastic damper. The results indicate that incorporating a damper of the design can significantly improve the seismic performance of steel frame structures.Keywords: cyclic loading, energy dissipation, hybrid damper, passive control system, viscoelastic damper
Procedia PDF Downloads 2011342 Adaptive Environmental Control System Strategy for Cabin Air Quality in Commercial Aircrafts
Authors: Paolo Grasso, Sai Kalyan Yelike, Federico Benzi, Mathieu Le Cam
Abstract:
The cabin air quality (CAQ) in commercial aircraft is of prime interest, especially in the context of the COVID-19 pandemic. Current Environmental Control Systems (ECS) rely on a prescribed fresh airflow per passenger to dilute contaminants. An adaptive ECS strategy is proposed, leveraging air sensing and filtration technologies to ensure a better CAQ. This paper investigates the CAQ level achieved in commercial aircraft’s cabin during various flight scenarios. The modeling and simulation analysis is performed in a Modelica-based environment describing the dynamic behavior of the system. The model includes the following three main systems: cabin, recirculation loop and air-conditioning pack. The cabin model evaluates the thermo-hygrometric conditions and the air quality in the cabin depending on the number of passengers and crew members, the outdoor conditions and the conditions of the air supplied to the cabin. The recirculation loop includes models of the recirculation fan, ordinary and novel filtration technology, mixing chamber and outflow valve. The air-conditioning pack includes models of heat exchangers and turbomachinery needed to condition the hot pressurized air bled from the engine, as well as selected contaminants originated from the outside or bled from the engine. Different ventilation control strategies are modeled and simulated. Currently, a limited understanding of contaminant concentrations in the cabin and the lack of standardized and systematic methods to collect and record data constitute a challenge in establishing a causal relationship between CAQ and passengers' comfort. As a result, contaminants are neither measured nor filtered during flight, and the current sub-optimal way to avoid their accumulation is their dilution with the fresh air flow. However, the use of a prescribed amount of fresh air comes with a cost, making the ECS the most energy-demanding non-propulsive system within an aircraft. In such a context, this study shows that an ECS based on a reduced and adaptive fresh air flow, and relying on air sensing and filtration technologies, provides promising results in terms of CAQ control. The comparative simulation results demonstrate that the proposed adaptive ECS brings substantial improvements to the CAQ in terms of both controlling the asymptotic values of the concentration of the contaminant and in mitigating hazardous scenarios, such as fume events. Original architectures allowing for adaptive control of the inlet air flow rate based on monitored CAQ will change the requirements for filtration systems and redefine the ECS operation.Keywords: cabin air quality, commercial aircraft, environmental control system, ventilation
Procedia PDF Downloads 911341 Development of Underactuated Robot Hand Using Cross Section Deformation Spring
Authors: Naoki Saito, Daisuke Kon, Toshiyuki Sato
Abstract:
This paper describes an underactuated robot hand operated by low-power actuators. It can grasp objects of various shapes using easy operations. This hand is suitable for use as a lightweight prosthetic hand that can grasp various objects using few input channels. To realize operations using a low-power actuator, a cross section deformation spring is proposed. The design procedure of the underactuated robot finger is proposed to realize an adaptive grasping movement. The validity of this mechanism and design procedure are confirmed through an object grasping experiment. Results demonstrate the effectiveness of a cross section deformation spring in reducing the actuator power. Moreover, adaptive grasping movement is realized by an easy operation.Keywords: robot hand, underactuated mechanism, cross-section deformation spring, prosthetic hand
Procedia PDF Downloads 3671340 Innovative Design Considerations for Adaptive Spacecraft
Authors: K. Parandhama Gowd
Abstract:
Space technologies have changed the way we live in the present day society and manage many aspects of our daily affairs through Remote sensing, Navigation & Communications. Further, defense and military usage of spacecraft has increased tremendously along with civilian purposes. The number of satellites deployed in space in Low Earth Orbit (LEO), Medium Earth Orbit (MEO), and the Geostationary Orbit (GEO) has gone up. The dependency on remote sensing and operational capabilities are most invariably to be exploited more and more in future. Every country is acquiring spacecraft in one way or other for their daily needs, and spacecraft numbers are likely to increase significantly and create spacecraft traffic problems. The aim of this research paper is to propose innovative design concepts for adaptive spacecraft. The main idea here is to improve existing design methods of spacecraft design and development to further improve upon design considerations for futuristic adaptive spacecraft with inbuilt features for automatic adaptability and self-protection. In other words, the innovative design considerations proposed here are to have future spacecraft with self-organizing capabilities for orbital control and protection from anti-satellite weapons (ASAT). Here, an attempt is made to propose design and develop futuristic spacecraft for 2030 and beyond due to tremendous advancements in VVLSI, miniaturization, and nano antenna array technologies, including nano technologies are expected.Keywords: satellites, low earth orbit (LEO), medium earth orbit (MEO), geostationary earth orbit (GEO), self-organizing control system, anti-satellite weapons (ASAT), orbital control, radar warning receiver, missile warning receiver, laser warning receiver, attitude and orbit control systems (AOCS), command and data handling (CDH)
Procedia PDF Downloads 2891339 Adaptive Neuro Fuzzy Inference System Model Based on Support Vector Regression for Stock Time Series Forecasting
Authors: Anita Setianingrum, Oki S. Jaya, Zuherman Rustam
Abstract:
Forecasting stock price is a challenging task due to the complex time series of the data. The complexity arises from many variables that affect the stock market. Many time series models have been proposed before, but those previous models still have some problems: 1) put the subjectivity of choosing the technical indicators, and 2) rely upon some assumptions about the variables, so it is limited to be applied to all datasets. Therefore, this paper studied a novel Adaptive Neuro-Fuzzy Inference System (ANFIS) time series model based on Support Vector Regression (SVR) for forecasting the stock market. In order to evaluate the performance of proposed models, stock market transaction data of TAIEX and HIS from January to December 2015 is collected as experimental datasets. As a result, the method has outperformed its counterparts in terms of accuracy.Keywords: ANFIS, fuzzy time series, stock forecasting, SVR
Procedia PDF Downloads 2381338 Micromechanical Compatibility Between Cells and Scaffold Mediates the Efficacy of Regenerative Medicine
Authors: Li Yang, Yang Song, Martin Y. M. Chiang
Abstract:
Objective: To experimentally substantiate the micromechanical compatibility between cell and scaffold, in the regenerative medicine approach for restoring bone volume, is essential for phenotypic transitions Methods: Through nanotechnology and electrospinning process, nanofibrous scaffolds were fabricated to host dental follicle stem cells (DFSCs). Blends (50:50) of polycaprolactone (PCL) and silk fibroin (SF), mixed with various content of cellulose nanocrystals (CNC, up to 5% in weight), were electrospun to prepare nanofibrous scaffolds with heterogeneous microstructure in terms of fiber size. Colloidal probe atomic force microscopy (AFM) and conventional uniaxial tensile tests measured the scaffold stiffness at the micro-and macro-scale, respectively. The cell elastic modulus and cell-scaffold adhesive interaction (i.e., a chemical function) were examined through single-cell force spectroscopy using AFM. The quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to determine if the mechanotransduction signal (i.e., Yap1, Wwr2, Rac1, MAPK8, Ptk2 and Wnt5a) is upregulated by the scaffold stiffness at the micro-scale (cellular scale). Results: The presence of CNC produces fibrous scaffolds with a bimodal distribution of fiber diameter. This structural heterogeneity, which is CNC-composition dependent, remarkably modulates the mechanical functionality of scaffolds at microscale and macroscale simultaneously, but not the chemical functionality (i.e., only a single material property is varied). In in vitro tests, the osteogenic differentiation and gene expression associated with mechano-sensitive cell markers correlate to the degree of micromechanical compatibility between DFSCs and the scaffold. Conclusion: Cells require compliant scaffolds to encourage energetically favorable interactions for mechanotransduction, which are converted into changes in cellular biochemistry to direct the phenotypic evolution. The micromechanical compatibility is indeed important to the efficacy of regenerative medicine.Keywords: phenotype transition, scaffold stiffness, electrospinning, cellulose nanocrystals, single-cell force spectroscopy
Procedia PDF Downloads 1781337 Evaluating Climate Risks to Enhance Resilience in Durban, South Africa
Authors: Cabangile Ncengeni Ngwane, Gerald Mills
Abstract:
Anthropogenic climate change is exacerbating natural hazards such as droughts, heat waves and sea-level rise. The associated risks are the greatest in places where socio-ecological systems are exposed to these changes and the populations and infrastructure are vulnerable. Identifying the communities at risk and enhancing local resilience are key issues in responding to the current and project climate changes. This paper explores the types of risks associated with multiple overlapping hazards in Durban, South Africa where the social, cultural and economic dimensions that contribute to exposure and vulnerability are compounded by its history of apartheid. As a result, climate change risks are highly concentrated in marginalized communities that have the least adaptive capacity. In this research, a Geographic Information System is to explore the spatial correspondence among geographic layers representing hazards, exposure and vulnerability across Durban. This quantitative analysis will allow authors to identify communities at high risk and focus our study on the nature of the current human-environment relationships that result in risk inequalities. This work will employ qualitative methods to critically examine policies (including educational practices and financial support systems) and on-the-ground actions that are designed to improve the adaptive capacity of these communities and meet UN Sustainable Development Goals. This work will contribute to a growing body of literature on disaster risk management, especially as it relates to developing economies where socio-economic inequalities are correlated with ethnicity and race.Keywords: adaptive capacity, disaster risk reduction, exposure, resilience, South Africa
Procedia PDF Downloads 1401336 [Keynote Talk]: Water Resources Vulnerability Assessment to Climate Change in a Semi-Arid Basin of South India
Authors: K. Shimola, M. Krishnaveni
Abstract:
This paper examines vulnerability assessment of water resources in a semi-arid basin using the 4-step approach. The vulnerability assessment framework is developed to study the water resources vulnerability which includes the creation of GIS-based vulnerability maps. These maps represent the spatial variability of the vulnerability index. This paper introduces the 4-step approach to assess vulnerability that incorporates a new set of indicators. The approach is demonstrated using a framework composed of a precipitation data for (1975–2010) period, temperature data for (1965–2010) period, hydrological model outputs and the water resources GIS data base. The vulnerability assessment is a function of three components such as exposure, sensitivity and adaptive capacity. The current water resources vulnerability is assessed using GIS based spatio-temporal information. Rainfall Coefficient of Variation, monsoon onset and end date, rainy days, seasonality indices, temperature are selected for the criterion ‘exposure’. Water yield, ground water recharge, evapotranspiration (ET) are selected for the criterion ‘sensitivity’. Type of irrigation and storage structures are selected for the criterion ‘Adaptive capacity’. These indicators were mapped and integrated in GIS environment using overlay analysis. The five sub-basins, namely Arjunanadhi, Kousiganadhi, Sindapalli-Uppodai and Vallampatti Odai, fall under medium vulnerability profile, which indicates that the basin is under moderate stress of water resources. The paper also explores prioritization of sub-basinwise adaptation strategies to climate change based on the vulnerability indices.Keywords: adaptive capacity, exposure, overlay analysis, sensitivity, vulnerability
Procedia PDF Downloads 3081335 Recycled Asphalt Pavement with Warm Mix Additive for Sustainable Road Construction
Authors: Meor Othman Hamzah, Lillian Gungat, Nur Izzi Md. Yusoff, Jan Valentin
Abstract:
The recent hike in raw materials costs and the quest for preservation of the environment has prompted asphalt industries to adopt greener road construction technology. This paper presents a study on such technology by means of asphalt recycling and use of warm mix asphalt (WMA) additive. It evaluates the effects of a WMA named RH-WMA on binder rheological properties and asphalt mixture performance. The recycled asphalt, obtained from local roads, was processed, fractionated, and incorporated with virgin aggregate and binder. For binder testing, the recycled asphalt was extracted and blended with virgin binder. The binder and mixtures specimen containing 30 % and 50 % recycled asphalt contents were mixed with 3 % RH-WMA. The rheological properties of the binder were evaluated based on fundamental, viscosity, and frequency sweep tests. Indirect tensile strength and resilient modulus tests were carried out to assess the mixture’s performances. The rheological properties and strength performance results showed that the addition of RH-WMA slightly reduced the binder and mixtures stiffness. The percentage of recycled asphalt increased the stiffness of binder and mixture, and thus improves the resistance to rutting. Therefore, the integration of recycled asphalt and RH-WMA can be an alternative material for road sustainable construction for countries in the tropics.Keywords: recycled asphalt, warm mix additive, rheological, mixture performance
Procedia PDF Downloads 5081334 Improving Patient-Care Services at an Oncology Center with a Flexible Adaptive Scheduling Procedure
Authors: P. Hooshangitabrizi, I. Contreras, N. Bhuiyan
Abstract:
This work presents an online scheduling problem which accommodates multiple requests of patients for chemotherapy treatments in a cancer center of a major metropolitan hospital in Canada. To solve the problem, an adaptive flexible approach is proposed which systematically combines two optimization models. The first model is intended to dynamically schedule arriving requests in the form of waiting lists whereas the second model is used to reschedule the already booked patients with the goal of finding better resource allocations when new information becomes available. Both models are created as mixed integer programming formulations. Various controllable and flexible parameters such as deviating the prescribed target dates by a pre-determined threshold, changing the start time of already booked appointments and the maximum number of appointments to move in the schedule are included in the proposed approach to have sufficient degrees of flexibility in handling arrival requests and unexpected changes. Several computational experiments are conducted to evaluate the performance of the proposed approach using historical data provided by the oncology clinic. Our approach achieves outstandingly better results as compared to those of the scheduling system being used in practice. Moreover, several analyses are conducted to evaluate the effect of considering different levels of flexibility on the obtained results and to assess the performance of the proposed approach in dealing with last-minute changes. We strongly believe that the proposed flexible adaptive approach is very well-suited for implementation at the clinic to provide better patient-care services and to utilize available resource more efficiently.Keywords: chemotherapy scheduling, multi-appointment modeling, optimization of resources, satisfaction of patients, mixed integer programming
Procedia PDF Downloads 1541333 Embedment Design Concept of Signature Tower in Chennai
Authors: M. Gobinath, S. Balaji
Abstract:
Assumptions in model inputs: Grade of concrete=40 N/mm2 (for slab), Grade of concrete=40 N/mm2 (for shear wall), Grade of Structural steel (plate girder)=350 N/mm2 (yield strength), Ultimate strength of structural steel=490 N/mm2, Grade of rebar=500 N/mm2 (yield strength), Applied Load=1716 kN (un-factored). Following assumptions are made for the mathematical modelling of RCC with steel embedment: (1) The bond between the structural steel and concrete is neglected. (2) The stiffener is provided with shear studs to transfer the shear force. Hence nodal connectivity is established between solid nodes (concrete) and shell elements (stiffener) at those locations. (3) As the end reinforcements transfer either tension/compression, it is modeled as line element and connected to solid nodes. (4) In order to capture the bearing of bottom flange on to the concrete, the line element of plan size of solid equal to the cross section of line elements is connected between solid and shell elements below for bottom flange and above for top flange. (5) As the concrete cannot resist tension at the interface (i.e., between structural steel and RCC), the tensile stiffness is assigned as zero and only compressive stiffness is enabled to take. Hence, non-linear static analysis option is invoked.Keywords: structure, construction, signature tower, embedment design concept
Procedia PDF Downloads 2941332 Adaptive Motion Compensated Spatial Temporal Filter of Colonoscopy Video
Authors: Nidhal Azawi
Abstract:
Colonoscopy procedure is widely used in the world to detect an abnormality. Early diagnosis can help to heal many patients. Because of the unavoidable artifacts that exist in colon images, doctors cannot detect a colon surface precisely. The purpose of this work is to improve the visual quality of colonoscopy videos to provide better information for physicians by removing some artifacts. This work complements a series of work consisting of three previously published papers. In this paper, Optic flow is used for motion compensation, and then consecutive images are aligned/registered to integrate some information to create a new image that has or reveals more information than the original one. Colon images have been classified into informative and noninformative images by using a deep neural network. Then, two different strategies were used to treat informative and noninformative images. Informative images were treated by using Lucas Kanade (LK) with an adaptive temporal mean/median filter, whereas noninformative images are treated by using Lucas Kanade with a derivative of Gaussian (LKDOG) with adaptive temporal median images. A comparison result showed that this work achieved better results than that results in the state- of- the- art strategies for the same degraded colon images data set, which consists of 1000 images. The new proposed algorithm reduced the error alignment by about a factor of 0.3 with a 100% successfully image alignment ratio. In conclusion, this algorithm achieved better results than the state-of-the-art approaches in case of enhancing the informative images as shown in the results section; also, it succeeded to convert the non-informative images that have very few details/no details because of the blurriness/out of focus or because of the specular highlight dominate significant amount of an image to informative images.Keywords: optic flow, colonoscopy, artifacts, spatial temporal filter
Procedia PDF Downloads 1091331 Effect of Tube Thickness on the Face Bending for Blind-Bolted Connection to Concrete Filled Tubular Structures
Authors: Mohammed Mahmood, Walid Tizani, Carlo Sansour
Abstract:
In this paper, experimental testing and numerical analysis were used to investigate the effect of tube thickness on the face bending for concrete filled hollow sections connected to other structural members using Extended Hollobolts. Six samples were tested experimentally by applying pull-out load on the bolts. These samples were designed to fail by column face bending. The main variable in all tests is the column face thickness. Finite element analyses were also performed using ABAQUS 6.11 to extend the experimental results and to quantify the effect of column face thickness. Results show that, the column face thickness has a clear impact on the connection strength and stiffness. However, the amount of improvement in the connection stiffness by changing the column face thickness from 5 mm to 6.3 mm seems to be higher than that when increasing it from 6.3 mm to 8 mm. The displacement at which the bolts start pulling-out from their holes increased with the use of thinner column face due to the high flexibility of the section. At the ultimate strength, the yielding of the column face propagated to the column corner and there was no yielding in its walls. After the ultimate resistance is reached, the propagation of the yielding was mainly in the column face with a miner yielding in the walls.Keywords: anchored bolted connection, Extended Hollobolt, column faces bending, concrete filled hollow sections
Procedia PDF Downloads 4161330 Early Requirement Engineering for Design of Learner Centric Dynamic LMS
Authors: Kausik Halder, Nabendu Chaki, Ranjan Dasgupta
Abstract:
We present a modelling framework that supports the engineering of early requirements specifications for design of learner centric dynamic Learning Management System. The framework is based on i* modelling tool and Means End Analysis, that adopts primitive concepts for modelling early requirements (such as actor, goal, and strategic dependency). We show how pedagogical and computational requirements for designing a learner centric Learning Management system can be adapted for the automatic early requirement engineering specifications. Finally, we presented a model on a Learner Quanta based adaptive Courseware. Our early requirement analysis shows that how means end analysis reveals gaps and inconsistencies in early requirements specifications that are by no means trivial to discover without the help of formal analysis tool.Keywords: adaptive courseware, early requirement engineering, means end analysis, organizational modelling, requirement modelling
Procedia PDF Downloads 4931329 A Dynamic Software Product Line Approach to Self-Adaptive Genetic Algorithms
Authors: Abdelghani Alidra, Mohamed Tahar Kimour
Abstract:
Genetic algorithm must adapt themselves at design time to cope with the search problem specific requirements and at runtime to balance exploration and convergence objectives. In a previous article, we have shown that modeling and implementing Genetic Algorithms (GA) using the software product line (SPL) paradigm is very appreciable because they constitute a product family sharing a common base of code. In the present article we propose to extend the use of the feature model of the genetic algorithms family to model the potential states of the GA in what is called a Dynamic Software Product Line. The objective of this paper is the systematic generation of a reconfigurable architecture that supports the dynamic of the GA and which is easily deduced from the feature model. The resultant GA is able to perform dynamic reconfiguration autonomously to fasten the convergence process while producing better solutions. Another important advantage of our approach is the exploitation of recent advances in the domain of dynamic SPLs to enhance the performance of the GAs.Keywords: self-adaptive genetic algorithms, software engineering, dynamic software product lines, reconfigurable architecture
Procedia PDF Downloads 2751328 Efficient Rehearsal Free Zero Forgetting Continual Learning Using Adaptive Weight Modulation
Authors: Yonatan Sverdlov, Shimon Ullman
Abstract:
Artificial neural networks encounter a notable challenge known as continual learning, which involves acquiring knowledge of multiple tasks over an extended period. This challenge arises due to the tendency of previously learned weights to be adjusted to suit the objectives of new tasks, resulting in a phenomenon called catastrophic forgetting. Most approaches to this problem seek a balance between maximizing performance on the new tasks and minimizing the forgetting of previous tasks. In contrast, our approach attempts to maximize the performance of the new task, while ensuring zero forgetting. This is accomplished through the introduction of task-specific modulation parameters for each task, and only these parameters are learned for the new task, after a set of initial tasks have been learned. Through comprehensive experimental evaluations, our model demonstrates superior performance in acquiring and retaining novel tasks that pose difficulties for other multi-task models. This emphasizes the efficacy of our approach in preventing catastrophic forgetting while accommodating the acquisition of new tasks.Keywords: continual learning, life-long learning, neural analogies, adaptive modulation
Procedia PDF Downloads 641327 A Typology System to Diagnose and Evaluate Environmental Affordances
Authors: Falntina Ahmad Alata, Natheer Abu Obeid
Abstract:
This paper is a research report of an experimental study on a proposed typology system to diagnose and evaluate the affordances of varying architectural environments. The study focused on architectural environments which have been developed with a shift in their use of adaptive reuse. The novelty in the newly developed environments was tested in terms of human responsiveness and interaction using a variety of selected cases. The study is a follow-up on previous research by the same authors, in which a typology of 16 categories of environmental affordances was developed and introduced. The current study introduced other new categories, which together with the previous ones establish what could be considered a basic language of affordance typology. The experiment was conducted on ten architectural environments while adopting two processes: 1. Diagnostic process, in which the environments were interpreted in terms of their affordances using the previously developed affordance typology, 2. The evaluation process, in which the diagnosed environments were evaluated using measures of emotional experience and architectural evaluation criteria of beauty, economy and function. The experimental study demonstrated that the typology system was capable of diagnosing different environments in terms of their affordances. It also introduced new categories of human interaction: “multiple affordances,” “conflict affordances,” and “mix affordances.” The different possible combinations and mixtures of categories demonstrated to be capable of producing huge numbers of other newly developed categories. This research is an attempt to draw a roadmap for designers to diagnose and evaluate the affordances within different architectural environments. It is hoped to provide future guidance for developing the best possible adaptive reuse according to the best affordance category within their proposed designs.Keywords: affordance theory, affordance categories, architectural environments, architectural evaluation criteria, adaptive reuse environment, emotional experience, shift in use environment
Procedia PDF Downloads 1831326 Climate Change Vulnerability and Capacity Assessment in Coastal Areas of Sindh Pakistan and Its Impact on Water Resources
Authors: Falak Nawaz
Abstract:
The Climate Change Vulnerability and Capacity Assessment carried out in the coastal regions of Thatta and Malir districts underscore the potential risks and challenges associated with climate change affecting water resources. This study was conducted by the author using participatory rural appraisal tools, with a greater focus on conducting focus group discussions, direct observations, key informant interviews, and other PRA tools. The assessment delves into the specific impacts of climate change along the coastal belt, concentrating on aspects such as rising sea levels, depletion of freshwater, alterations in precipitation patterns, fluctuations in water table levels, and the intrusion of saltwater into rivers. These factors have significant consequences for the availability and quality of water resources in coastal areas, manifesting in frequent migration and alterations in agriculture-based livelihood practices. Furthermore, the assessment assesses the adaptive capacity of communities and organizations in these coastal regions to effectively confront and alleviate the effects of climate change on water resources. It considers various measures, including infrastructure enhancements, water management practices, adjustments in agricultural approaches, and disaster preparedness, aiming to bolster adaptive capacity. The study's findings emphasize the necessity for prompt actions to address identified vulnerabilities and fortify the adaptive capacities of Sindh's coastal areas. This calls for comprehensive strategies and policies promoting sustainable water resource management, integrating climate change considerations, and providing essential resources and support to vulnerable communities.Keywords: climate, climate change adaptation, disaster reselience, vulnerability, capacity, assessment
Procedia PDF Downloads 541325 Settlement of the Foundation on the Improved Soil: A Case Study
Authors: Morteza Karami, Soheila Dayani
Abstract:
Deep Soil Mixing (DSM) is a soil improvement technique that involves mechanically mixing the soil with a binder material to improve its strength, stiffness, and durability. This technique is typically used in geotechnical engineering applications where weak or unstable soil conditions exist, such as in building foundations, embankment support, or ground improvement projects. In this study, the settlement of the foundation on the improved soil using the wet DSM technique has been analyzed for a case study. Before DSM production, the initial soil mixture has been determined based on the laboratory tests and then, the proper mix designs have been optimized based on the pilot scale tests. The results show that the spacing and depth of the DSM columns depend on the soil properties, the intended loading conditions, and other factors such as the available space and equipment limitations. Moreover, monitoring instruments installed in the pilot area verify that the settlement of the foundation has been placed in an acceptable range to ensure that the soil mixture is providing the required strength and stiffness to support the structure or load. As an important result, if the DSM columns touch or penetrate into the stiff soil layer, the settlement of the foundation can be significantly decreased. Furthermore, the DSM columns should be allowed to cure sufficiently before placing any significant loads on the structure to prevent excessive deformation or settlement.Keywords: deep soil mixing, soil mixture, settlement, instrumentation, curing age
Procedia PDF Downloads 771324 Evaluating the Fire Resistance of Offshore Tubular K-Joints Subjected to Balanced Axial Loads
Authors: Neda Azari Dodaran, Hamid Ahmadi
Abstract:
Results of 405 finite element (FE) analyses were used in the present research to study the effect of the joint geometry on the ultimate strength and initial stiffness of tubular K-joints subjected to axial loading at fire-induced elevated temperatures. The FE models were validated against the data available from experimental tests. Structural behavior under different temperatures (200ºC, 400ºC, 500ºC, and 700ºC) was investigated and compared to the behavior at ambient temperature (20ºC). A parametric study was conducted to investigate the effect of dimensionless geometrical parameters (β, γ, θ, and τ) on the ultimate strength and initial stiffness. Afterwards, ultimate strength data extracted from the FE analyses were compared with the values calculated from the equations proposed by available design codes in which the ultimate strength of the joint at elevated temperatures is obtained by replacing the yield stress of the steel at ambient temperature with the corresponding value at elevated temperature. It was indicated that this method may not have acceptable accuracy for K-joints under axial loading. Hence, a design formula was developed, through nonlinear regression analyses, to determine the ultimate strength of K-joints subjected to balanced axial loads at elevated temperatures.Keywords: axial loading, elevated temperature, parametric equation, static strength, tubular K-joint
Procedia PDF Downloads 1451323 Integrated Target Tracking and Control for Automated Car-Following of Truck Platforms
Authors: Fadwa Alaskar, Fang-Chieh Chou, Carlos Flores, Xiao-Yun Lu, Alexandre M. Bayen
Abstract:
This article proposes a perception model for enhancing the accuracy and stability of car-following control of a longitudinally automated truck. We applied a fusion-based tracking algorithm on measurements of a single preceding vehicle needed for car-following control. This algorithm fuses two types of data, radar and LiDAR data, to obtain more accurate and robust longitudinal perception of the subject vehicle in various weather conditions. The filter’s resulting signals are fed to the gap control algorithm at every tracking loop composed by a high-level gap control and lower acceleration tracking system. Several highway tests have been performed with two trucks. The tests show accurate and fast tracking of the target, which impacts on the gap control loop positively. The experiments also show the fulfilment of control design requirements, such as fast speed variations tracking and robust time gap following.Keywords: object tracking, perception, sensor fusion, adaptive cruise control, cooperative adaptive cruise control
Procedia PDF Downloads 2251322 The Elastic Field of a Nano-Pore, and the Effective Modulus of Composites with Nano-Pores
Authors: Xin Chen, Moxiao Li, Xuechao Sun, Fei Ti, Shaobao Liu, Feng Xu, Tian Jian Lu
Abstract:
The composite materials with pores have the characteristics of light weight, sound insulation, and heat insulation, and have broad prospects in many fields, including aerospace. In general, the stiffness of such composite is less than the stiffness of the matrix material, limiting their applications. In this paper, we establish a theoretical model to analyze the deformation mechanism of a nano-pore. The interface between the pores and matrix material is described by the Gurtin-Murdoch model. By considering scale effect related with current deformation, we estimate the effective mechanical properties (e.g., effective shear modulus and bulk modulus) of a composite with nano-pores. Due to the scale effect, the elastic field in the composite was changed and local hardening was observed around the nano-pore, and the effective shear modulus and effective bulk modulus were found to be a function of the surface energy. The effective shear modulus increase with the surface energy and decrease with the size of the nano-pores, and the effective bulk modulus decrease with the surface energy and increase with the size of the nano-pores. These results have potential applications in the nanocomposite mechanics and aerospace field.Keywords: composite mechanics, nano-inhomogeneity, nano-pores, scale effect
Procedia PDF Downloads 1281321 Knowledge Representation Based on Interval Type-2 CFCM Clustering
Authors: Lee Myung-Won, Kwak Keun-Chang
Abstract:
This paper is concerned with knowledge representation and extraction of fuzzy if-then rules using Interval Type-2 Context-based Fuzzy C-Means clustering (IT2-CFCM) with the aid of fuzzy granulation. This proposed clustering algorithm is based on information granulation in the form of IT2 based Fuzzy C-Means (IT2-FCM) clustering and estimates the cluster centers by preserving the homogeneity between the clustered patterns from the IT2 contexts produced in the output space. Furthermore, we can obtain the automatic knowledge representation in the design of Radial Basis Function Networks (RBFN), Linguistic Model (LM), and Adaptive Neuro-Fuzzy Networks (ANFN) from the numerical input-output data pairs. We shall focus on a design of ANFN in this paper. The experimental results on an estimation problem of energy performance reveal that the proposed method showed a good knowledge representation and performance in comparison with the previous works.Keywords: IT2-FCM, IT2-CFCM, context-based fuzzy clustering, adaptive neuro-fuzzy network, knowledge representation
Procedia PDF Downloads 3171320 An Improved Dynamic Window Approach with Environment Awareness for Local Obstacle Avoidance of Mobile Robots
Authors: Baoshan Wei, Shuai Han, Xing Zhang
Abstract:
Local obstacle avoidance is critical for mobile robot navigation. It is a challenging task to ensure path optimality and safety in cluttered environments. We proposed an Environment Aware Dynamic Window Approach in this paper to cope with the issue. The method integrates environment characterization into Dynamic Window Approach (DWA). Two strategies are proposed in order to achieve the integration. The local goal strategy guides the robot to move through openings before approaching the final goal, which solves the local minima problem in DWA. The adaptive control strategy endows the robot to adjust its state according to the environment, which addresses path safety compared with DWA. Besides, the evaluation shows that the path generated from the proposed algorithm is safer and smoother compared with state-of-the-art algorithms.Keywords: adaptive control, dynamic window approach, environment aware, local obstacle avoidance, mobile robots
Procedia PDF Downloads 1461319 A New Low Cost Seismic Response Controlling Structures with Semi Base Isolation Devices
Authors: M. Ezati Kooshki, A. Abbaszadeh Shahri
Abstract:
A number of devices used to control seismic structures have been developed during the past decades. One of the effective ways to reduce seismic forces transmitted to the buildings is through the base isolation systems, but the use of these devices is currently limited to large and expensive buildings. This study was an attempt to introduce an effective and low cost way to protect of structures against grand motions by a semi base isolation system. In this new way, structures were not completely decoupled of bases and the natural frequency of structures was changed due to earthquake by changing the horizontal stiffness; therefore, ground excitation energy was dissipated before entering the structures. For analyzing the dynamic behavior, the new method used finite element software (ABAQUS 6-10-1). This investigation introduced a new package of semi base isolation devices with a new material constitutive, but common in automobile industries, seeking to evaluate the effects of additional new devices on the seismic response when compared with structures without additional devises for different ground motions. The proposed semi base isolation devices were applied to a one story frame and the time history analysis was conducted on the record of Kobe earthquake (1995). The results showed that the efficiency reduced the floor acceleration and displacement, as well as velocity.Keywords: semi base isolation system, finite element, natural frequency, horizontal stiffness
Procedia PDF Downloads 3911318 Video Foreground Detection Based on Adaptive Mixture Gaussian Model for Video Surveillance Systems
Authors: M. A. Alavianmehr, A. Tashk, A. Sodagaran
Abstract:
Modeling background and moving objects are significant techniques for video surveillance and other video processing applications. This paper presents a foreground detection algorithm that is robust against illumination changes and noise based on adaptive mixture Gaussian model (GMM), and provides a novel and practical choice for intelligent video surveillance systems using static cameras. In the previous methods, the image of still objects (background image) is not significant. On the contrary, this method is based on forming a meticulous background image and exploiting it for separating moving objects from their background. The background image is specified either manually, by taking an image without vehicles, or is detected in real-time by forming a mathematical or exponential average of successive images. The proposed scheme can offer low image degradation. The simulation results demonstrate high degree of performance for the proposed method.Keywords: image processing, background models, video surveillance, foreground detection, Gaussian mixture model
Procedia PDF Downloads 511