436 research outputs found
Comparison of Manning's Roughness Coefficient Estimation Methods Based on Channel Geometry and Bed-Load Sediment Characteristics in the Way Tapus River
No full textNatural and artificial rivers contain bed-load sediment materials with varying shapes and grain sizes influencing flow resistance, velocity, and discharge. This resistance is expressed by the Manning roughness coefficient (n), whose accurate estimation is essential for hydraulic analysis. While n is commonly obtained from Manning’s table, alternative methods based on hydraulic parameters, channel geometry, and sediment characteristics, such as the Keulegan, Mayer-Peter-Muller, Lane and Carlson, Henderson, Raudkivi, Subramanya, and Wong and Parker methods, can be applied for more site-specific estimations. This study utilized primary field data and secondary data to estimate n values using various approaches. The n values ranged from 0.096–0.148 (hydraulic parameters), 0.069–0.136 (channel geometry), and 0.009–0.018 (sediment-based methods). Error analysis comparing calculated and observed discharges showed that the channel geometry method yielded the most accurate results with an average error of 15.59%. In contrast, other methods resulted in significantly higher errors. Thus, the channel geometry approach is recommended for estimating the Manning coefficient in the Way Tapus River.Natural and artificial rivers contain bed-load sediment materials with varying shapes and grain sizes influencing flow resistance, velocity, and discharge. This resistance is expressed by the Manning roughness coefficient (n), whose accurate estimation is essential for hydraulic analysis. While n is commonly obtained from Manning’s table, alternative methods based on hydraulic parameters, channel geometry, and sediment characteristics, such as the Keulegan, Mayer-Peter-Muller, Lane and Carlson, Henderson, Raudkivi, Subramanya, and Wong and Parker methods, can be applied for more site-specific estimations. This study utilized primary field data and secondary data to estimate n values using various approaches. The n values ranged from 0.096–0.148 (hydraulic parameters), 0.069–0.136 (channel geometry), and 0.009–0.018 (sediment-based methods). Error analysis comparing calculated and observed discharges showed that the channel geometry method yielded the most accurate results with an average error of 15.59%. In contrast, other methods resulted in significantly higher errors. Thus, the channel geometry approach is recommended for estimating the Manning coefficient in the Way Tapus River
Optimal Offline TCP Sender Buffer Management Strategy
No full textThe participation of the first author in multiple algorithmic contests (both as a contestant and as a member of the scientific committee) influenced many of the results presented in this paper. The attached ZIP archive contains a few sample tasks and solutions (of the first author or of others) which are related to some of the algorithms and data structures proposed in this paper. The final version of the paper can be found in the IEEE Xplore database: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=4561173&queryText%3DOptimal+Offline+TCP+Sender+Buffer+Management+StrategyInternational audienceThe Transmission Control Protocol (TCP) uses a sliding window in order to enforce flow control. The receiver advertises its available buffer space to the sender, which cannot transmit more data than the advertised space. Transmitted data is first copied from application buffers into TCP buffers and from there it is sent through the network. In this paper we propose a model which characterizes the sender's behavior throughout the duration of a TCP conversation. The model is suitable in the case of powerful, but variably loaded senders, slow receivers, fast connections and moderate amounts of data transmitted. For this model we present an O(n∙log2n) algorithm which computes the minimum processing time spent by the sender, if the window sizes advertised by the receiver and the sender's load are known in advance. The solution is based on an algorithmic framework for the segment tree data structure, which we introduce in this paper
The EnrichMe project: A robotic solution for independence and active aging of elderly people with MCI
No full textMild cognitive impairment (MCI) is a state related to ageing, and sometimes evolves to dementia. As there is no pharmacological treatment for MCI, a non-pharmacological approach is very important. The use of Information and Communication Technologies (ICT) in care and assistance services for elderly people increases their chances of prolonging independence thanks to better cognitive efficiency. Robots are seen to have the potential to support the care and independence of elderly people. The project ENRICHME (funded by the EU H2020 Programme) focuses on developing and testing technologies for supporting elderly people with MCI in their living environment for a long time. This paper describes the results of the activities conducted during the first year of the ENRICHME project, in particular the definition of user needs and requirements and the resulting system architecture
Efficient Data Structures for Online QoS-Constrained Data Transfer Scheduling
No full textThe participation of the first author in multiple algorithmic contests (both as a contestant and as a member of the scientific committee) influenced many of the results presented in this paper. The attached ZIP archive contains a few sample tasks and solutions (of the first author or of others) which are related to some of the data structures presented in this paper. The final version of the paper can be found in the IEEE Xplore database: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=4724258&queryText%3DEfficient+Data+Structures+for+Online+QoS-Constrained+Data+Transfer+SchedulingInternational audienceDistributed applications and services requiring the transfer of large amounts of data have been developed and deployed all around the world. The best effort behavior of the Internet cannot offer to these applications the necessary Quality of Service (QoS) guarantees, making the development of data transfer scheduling techniques a necessity. In this paper we propose novel methods of efficiently using some well-known data structures (e.g. the segment tree and the block partition), which can be implemented in a resource manager (e.g. Grid job scheduler, bandwidth broker) in order to serve quickly large numbers of advance resource reservation and allocation requests
Optimal Scheduling of Two Communication Flows on Multiple Disjoint Packet-Type Aware Paths
No full textThe participation of the first author in multiple algorithmic contests (both as a contestant and as a member of the scientific committee) influenced many of the results presented in this paper. The attached ZIP archive contains a few sample tasks and solutions (of the first author or of others) which are related to some of the algorithms and data structures discussed in this paper. The final version of the paper can be found in the IEEE Xplore database: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=5204801&queryText%3DOptimal+Scheduling+of+Two+Communication+Flows+on+Multiple+Disjoint+Packet-Type+Aware+PathsInternational audienceCommunication flows in distributed systems often present a poor performance, because they are unaware of each other and end up competing for the same bottleneck resources. A solution to this problem consists of scheduling the communication flows in order to optimize some performance metric. In this paper we study the scheduling of two communication flows over several disjoint paths, such that the maximum completion time (makespan) is minimized. Each flow i is composed of a large number of identical packets of the same type i (i=1,2). The paths are aware of the packet types and have different transmission times for each type. We present the characteristics of optimal schedules for minimizing the makespan. Afterwards, we consider the objective of minimizing the sum of completion times and present two dynamic programming algorithms for this case
Constrained Content Distribution and Communication Scheduling for Several Restricted Classes of Graphs
No full textThe participation of the first author in multiple algorithmic contests (both as a contestant and as a member of the scientific committee) influenced many of the results presented in this paper. The attached ZIP archive contains a few sample tasks and solutions (of the first author or of others) which are related to some of the algorithms presented in this paper. The final version of the paper can be found in the IEEE Xplore database: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=5204800&queryText%3DConstrained+Content+Distribution+and+Communication+Scheduling+for+Several+Restricted+Classes+of+GraphsInternational audienceIn this paper we address several problems regarding content distribution (broadcast) and communication scheduling for some restricted classes of graphs (trees, intersecting cliques, graphs with multiple disjoint paths). For the broadcast problem in trees we introduce some new extensions and present some new algorithmic results for determining optimal offline broadcast strategies. The communication scheduling problems are also addressed from an offline algorithmic perspective, considering multiple disjoint paths, mutual exclusion constraints or one-dimensional geometric aspects
Time Slot Groups - A Data Structure for QoS-Constrained Advance Bandwidth Reservation and Admission Control
No full textThe algorithmic techniques presented in this paper were used by the first author in algorithmic programming contests (the attached zip archive contains a few sample contest tasks and solutions of the authors as well as official solutions from the respective contests). The IEEE Xplore link to the final published version of the paper is here: http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=5204837&contentType=Conference+Publications&queryText%3DTime+Slot+Groups+-+A+Data+Structure+for+QoS-Constrained+Advance+Bandwidth+Reservation+and+Admission+ControlInternational audienceIn this paper we present Time Slot Groups (TSG), a novel, efficient data structure for QoS-constrained advance bandwidth reservation and admission control. The data structure divides the time horizon into T equally sized time slots and can be used for serving efficiently complex bandwidth reservation requests specifying the duration of the reservation, the minimum required bandwidth, the earliest possible starting time and the latest possible finish time. The data structure supports reservation queries in time O(k+(T/k)*log(k)) and reservation updates in time O(k+(T/k)), where k is a user-defined parameter
How do driving modes affect the vehicle’s dynamic behaviour? Comparing Renault’s Multi-Sense sport and comfort modes during on-road naturalistic driving
No full textSeveral modern vehicles provide the option to select a driving mode. However, the literature contains no empirical studies that investigate how driving modes affect the vehicle's dynamic behaviour in regular on-road driving. We examined for which CAN-bus signals the differences between Renault's Multi-Sense® comfort and sport modes are most apparent. We gathered data on a 26.3 km route containing a rural and highway section. A single person drove the route four times in comfort mode and four times in sport mode. By statistically analysing and ordering 887 CAN-bus signals, we found strong differences between the two modes for rear-wheel angle, engine torque, longitudinal acceleration, and vertical motion. Parameter identification of a quarter car model identified a 3.5 times higher damping coefficient for the sport mode compared to the comfort mode. Due to four wheel steering, compared to the comfort mode, the sport mode yielded a higher lateral acceleration and yaw rate for a given steering wheel angle and driving speed. In conclusion, this study provides quantitative insight into the extent to which the Multi-Sense driving modes impact the vehicle's lateral, longitudinal, and vertical dynamic behaviour. The results and the analysis methods help guide future driving mode designs.Human-Robot Interactio
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